DTSquared Posted February 5, 2018 Report Share Posted February 5, 2018 Hello, I am rather new to refinishing and have been watching many of the videos/reading the forums. I have been searching for an answer to refinishing a John Boos walnut butcher block top that originally had a mineral oil topcoat. The edges on the top were pretty sharp so I rounded them slightly and then sanded the whole top starting with 100 and then 150 and a light wash with Mineral Spirits. My paper is still gumming on the edges so I am concerned the mineral oil has not "dried" enough. The top and bottom look almost raw again and are mostly powdering when sanding. Eventually, I would like to apply one coat of Seal-a-Cell followed by two coats of Arm-r-Seal sanding between coats with 320. I am concerned that the mineral oil may interfere with the GF oil topcoats and have see the question asked many of times about this but usually the OP never returns to give an update. I have done a small test on the underside and both the Seal-a-Cell and Arm-a-Seal are drying but perhaps this small test is not enough. I have seen several answers that suggest a seal coat with dewaxed shellac and others with washing down with Naptha or Acetone. John Boos sells a product called "Ez-Do" which is manufactured by Lawrence McFadden and is very similar to GF's Gel Topcoat. With Ez-Do it says you can use over a mineral oil top as long as it has been wiped dry and has been on at least 72 hours. I have been using the Arm-r-Seal on some raw walnut shelves and really like the result so far. I would like the shelves and top to look similar and have the same level of protection. If the Ez-do can be applied to a mineral oil top, I can see no reason why GF products should be a problem either. Here is a link to the Ez-do product and the MSDS: https://ardec.ca/en/p/415/ez-do Can I eventually proceed with the Arm-r-Seal or just use Ez-do? Are there any other recommendations you might all have? Thanks, DT Quote Link to comment Share on other sites More sharing options...
DTSquared Posted February 5, 2018 Author Report Share Posted February 5, 2018 I just wanted to add that I do not plan on using the countertop for cutting purposes nor food prep. It will be house small appliances (coffee grinder, coffee pot, toaster). Hence, the need for a more durable finish. Hope someone can help! Thanks in advance. Quote Link to comment Share on other sites More sharing options...
drzaius Posted February 5, 2018 Report Share Posted February 5, 2018 Mineral oil will never cure, or "dry". I don't give high chances that you can get any sort of film finish to adhere well. The best shot would probably be extensive, thorough and numerous washes with naptha, followed by shellac & then Arm-R-Seal. But the question is, why do you want to refinish the board with poly? If you do, it'll be no good as a cutting board anymore. the poly will just come off a little bit at a time every time you put a knife to it. And that's even if you had perfect prep & perfect adhesion. If you want to continue to use it, then just reapply mineral oil, or an oil/beeswax blend. Then repeat every few months or as required. 1 Quote Link to comment Share on other sites More sharing options...
wdwerker Posted February 5, 2018 Report Share Posted February 5, 2018 If it's just a countertop & not an end grain cutting board then the arm-r-seal makes some sense. Quote Link to comment Share on other sites More sharing options...
DTSquared Posted February 5, 2018 Author Report Share Posted February 5, 2018 Yes, I will only use it as a countertop. Absolutely NO cutting (I use poly boards). Just want to protect against normal wear and tear. Since I will never be cutting or prepping, I would like the easier maintenance of the ARS rather than oiling with MO/Beeswax once a month. On the underside, I tested the Seal-a-Cell (overnight dry) followed by the Arm-r-Seal. The Seal-a-Cell dried. Unfortunately, it doesn't look like the ARM will dry over that. I have a test area of the GF Gel Top Coat and a test area of the Ez-Do. If I can't feel comfortable with ARS, then I will default to the Ez-Do as that it was intended for -- go over old mineral oil finish or when the varnish finish is worn/cut. I appreciate the input so far. Quote Link to comment Share on other sites More sharing options...
difalkner Posted February 6, 2018 Report Share Posted February 6, 2018 I'm in agreement; I don't think you'll ever see mineral oil dry. And it would take a lot of Naphtha to get it out of the board. Not saying you can't get it done but it's not going to be a quick, overnight task. David Quote Link to comment Share on other sites More sharing options...
DTSquared Posted February 6, 2018 Author Report Share Posted February 6, 2018 Thanks everyone. I will not use ARS. I sanded it down to pretty much bare wood, but not going to take my chances. Did find this info on another woodworker's site. Makes sense why the Ez-Do is approved by Boos. I learned another important lesson. What finish can be put over mineral oil? This question has been around for many years. There are those who say nothing can be put over mineral oil, and there are those who say that they do it all the time. As we would expect, the answer is somewhere in between. Mineral oil is a petroleum product. In the simplest of terms, it could be described as highly refined and edible lubricating oil. As such, it does not dry when it is applied to the wood. Mineral oil is soluble in all petroleum based thinners and turpentine, and any finish that uses these same solvents can be put over it. Lacquer, shellac, varnish, and drying oils will absorb any mineral oil that is already in the wood into the new finish, and there will be no adhesion problems. However, there is a penalty. The mineral oil acts as a "plasticiser", and the new mixture will cure to a softer finish than if it were used alone over bare wood. How much softer will depend on how much mineral oil is present. And, the softer finish will deteriorate with age much faster than if it were applied over bare wood. If you are willing to accept this compromise, then the answer is that, yes, a finish can be applied over mineral oil. Quote Link to comment Share on other sites More sharing options...
Brendon_t Posted February 6, 2018 Report Share Posted February 6, 2018 My dad has a maple pig cutting board be made in his dad's shop as a teen. He asked me to refinish it to now be a centerpiece with a little shine. None of the testing I did with arm r seal over mineral spirits at least a year old were to my satisfaction. Ended up applying a thick hard wax finish and buffing it to the desired shine. That initial buffing still looks great on the kitchenette dine in holding a bowl of oranges and that's been about 18 months Quote Link to comment Share on other sites More sharing options...
wdwerker Posted February 6, 2018 Report Share Posted February 6, 2018 Pig shaped or for cutting up a pig on ? Similar wording but far different uses that imply a much bigger cutting board. Quote Link to comment Share on other sites More sharing options...
Brendon_t Posted February 6, 2018 Report Share Posted February 6, 2018 9 hours ago, wdwerker said: Pig shaped or for cutting up a pig on ? Similar wording but far different uses that imply a much bigger cutting board. Definately not suitable to carving up a whole pig on. It looks like he looked at a piggy bank and cut out that shape. Quote Link to comment Share on other sites More sharing options...
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